1. Field of the Invention
This invention relates to a catalytic process for producing gas mixtures containing hydrogen and carbon monoxide by reforming light hydrocarbons. More particularly, the present invention provides a process for producing gas mixtures containing hydrogen and carbon monoxide by reforming methane in the presence of specially prepared reforming catalysts.
2. Description of the Art
Light hydrocarbon and, more particularly, methane reforming processes are well known. Generally, hydrocarbon oxidation of hydrocarbons using an oxygen containing gas as the oxidant. Typically, methane reforming processes produce gas mixtures containing carbon monoxide/hydrogen ratios of 1/3 according to the following chemical equation: EQU CH.sub.4 +H.sub.2 O 1 CO+3 H.sub.2 (I)
Since gas mixtures containing carbon monoxide/hydrogen ratios of 1/1 or 1/2 are particularly useful as feed gases in processes for producing higher hydrocarbons and oxygenated derivatives, such as Fischer-Tropsch and alcohol synthesis processes, a higher ratio of carbon monoxide/hydrogen is necessary. In order to increase the carbon monoxide content, a water gas shift reaction must be employed according to the following chemical equation: EQU CO.sub.2 +H.sub.2 CO+H.sub.2 O (II)
Other processes for reforming hydrocarbons proceed by contacting the hydrocarbons with carbon dioxide, oxygen, steam or mixtures thereof. By varying the process conditions, methane reformation product gas mixtures could be obtained containing approximately a carbon monoxide/hydrogen ratio of between 2/1 to 1/1.
The reforming catalyst used in the above processes, generally Group VIII metals on various supports, have a tendency to liberate free carbon during the reforming process with the elemental carbon depositing on the catalyst. This deposition of carbon on the catalyst usually causes a significant decrease in the catalyst activity and, more importantly, often causes total disintegration of the catalyst. Thus, it would be highly desirable to catalytically reform light hydrocarbons at mild reaction conditions using a catalyst which is specifically suited to retain its activity during the reaction for long periods of time.
It is an object of the present invention to provide a catalytic process for reforming a light hydrocarbon and, more particularly, methane containing gases to obtain a product gas mixture containing hydrogen and carbon monoxide.
It is a further object of the present invention to provide a hydrocarbon reforming process which utilizes a specially prepared catalyst which is highly selective, highly resistant to carbon deposition, retains high activity even after deposition of carbon and allows for easy carbon removal without detrimental effect to the catalyst.